1) Field of the Invention
The present invention relates to a semiconductor pressure sensor, and specifically to a semiconductor pressure sensor having a thin diaphragm. This invention is also concerned with a fabrication process thereof, which makes use of an alignment mark.
2) Description of the Related Art
Semiconductor pressure sensors are used in various apparatuses such as automobiles and measuring instruments, since their performance including sensitivity is excellent despite of their reduced size and weight.
A conventional pressure sensor, as described by S. Sugiyama et al. in the article "One-Chip Integrated Pressure Sensor", T.IEE Japan, 109-C(12), 855-861 (1989), has a piezo resistance element formed over a diaphragm so that the piezo resistance element can sense pressures applied thereto in terms of variations in the resistivity thereof.